1. Field of the Invention
This invention relates to a prosthesis for replacement of arthritic or damaged elbow joints. More particularly, it concerns a form of elbow joint prosthesis that has good joint stability with minimum bone removal while providing normal flexion and extension motion; there is no in-built constraint and so little strain on the seating of the prosthesis.
2. Description of the Prior Art
In general, prosthetic replacement of the elbow has proved a difficult and often disappointing task over the years and this has been the experience of most surgeons in this field. In the past, it was common to replace the elbow joint by means of a constrained prosthesis, usually consisting of a large stem inserted into the humerus and another into the ulna and the two parts of the component linked together by an axle pin. The strong forces on the elbow tend to disrupt the prosthesis from the bone and a very great deal of bone had to be removed to put in such a prosthesis, resulting in the long-term in a disastrous situation very often if the prosthesis has, in fact, to be removed.
There has been a move in recent times to a surface replacement of the elbow joint and my work in this area led to the development of a constrained device with a T-slot stability factor which is described in U.S. Pat. No. 4,079,469. Numerous other U.S. patents have issued describing bone joint prosthesis of which the following is a representative listing: Nos.
2,784,416 PA1 3,547,115 PA1 3,748,662 PA1 3,798,679 PA1 3,801,990 PA1 3,816,854 PA1 3,840,905 PA1 3,852,831 PA1 3,869,729 PA1 3,886,599 PA1 3,919,725 PA1 3,990,116
In spite of the numerous procedures and devices previously developed and used for elbow reconstruction, there exists a need for further improvement particularly as regards resulting joint stability, minimal removal of bone for insertion and allowance for normal flexion and extension motion as well as minimal strain on the seating of the prosthesis.